缝洞型储层缝宽动态变化及其对钻井液漏失的影响  

Dynamic variation of fracture width and its effects on drilling fluid lost circulation in fractured vuggy reservoirs

作　　者：李大奇[1] 康毅力[1] 曾义金[2] 练章华[1] 杜春潮 

机构地区：[1]西南石油大学油气藏地质及开发工程国家重点实验室,四川成都610500 [2]中石化石油工程技术研究院,北京100101 [3]中石化西北油田分公司,新疆乌鲁木齐830013

出　　处：《中国石油大学学报（自然科学版）》2011年第5期76-81,共6页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家'973'计划课题(2010CB226705);国家科技重大专项课题(2008ZX05049-003-07HZ2;008ZX05005-006-08HZ)

摘　　要：以塔河油田12区为例,根据缝洞型碳酸盐岩储层的地质特征,建立考虑溶洞存在和漏失动态的有限元模型,研究裂缝的宽度变化规律及其对钻井液漏失的影响。结果表明:缝洞型储层裂缝宽度对井筒有效压力极为敏感,在几兆帕的正压差下,裂缝宽度增量便可达毫米级;钻井液漏失使得裂缝变宽,裂缝形态也相应地发生改变,增加了漏失控制难度;除了缝洞发育外,缝洞型储层的强应力敏感性也是井漏的重要原因之一;钻井中精细控制井筒压力,保持井筒压力微过平衡,并在钻进储层段前随钻加入毫米级高酸溶性暂堵堵漏材料,可以有效预防大部分漏失发生。Based on the geological condition of Tahe Oilfield area 12, a finite element model considering vuggy and drilling fluid losses was established and the fracture width change and its effects on lost circulation were researched by using the model and the drilling practices. The results show that the fracture width is extremely sensitive to the wellbore pressure in fractured vuggy reservoirs, and the fracture width increments will be up to millimeter-level under the positive pressure difference of several mega pascal. Drilling fluid losses would make the fracture width become wider and change the fracture morphology accordingly, which increases the difficulty of drilling fluid losses control. The strong stress sensitivity is one of main reasons of lost circulation besides the development of fractured vuggy. Then, precisely managing the wellbore pressure, keeping slightly over balance pressure, and adding millimeter-level high acid soluble bridging materials to drilling fluid during drilling the reservoir section can prevent drilling fluid losses.

关 键 词：缝洞型储层 裂缝宽度 井漏 防漏堵漏 数值模拟 

分 类 号：TE258[石油与天然气工程—油气井工程]